JP2963546B2 - Recording head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head, and more particularly, to a thermal head or a bubble jet head used in a printer or the like.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view of an essential part for explaining an example of a conventional thermal head. In the drawing, 1 is a substrate, 2 is a heating resistor layer, 3 is a selection electrode, 4 is a common electrode, and 5 is a common electrode. Is a protective layer,
6 is a common electrode reinforcing member, 7 is a bonding pad portion of a lead wire, and 8 is a heating portion. As is well known, a selection electrode is formed on the heating resistor layer 2 so as to form an opening serving as the heating portion 8. 3
And the common electrode 4, and the heat generating portion 8 is covered with a protective layer 5, and a current flows between the selection electrode 3 and the common electrode 4 through the heat generating resistor 2 in accordance with a recording signal. 2, heat is generated and heat-sensitive recording is performed.
Thus, in the conventional thermal head as described above, the common electrode 4 was provided on the paper discharge side as shown in the figure, and its width was about 3 mm. However, this type of thermal head has problems in terms of miniaturization, voltage drop at a common electrode, and the like.
Folding molds are beginning to be applied.

FIG. 3 is a cross-sectional view of an essential part for explaining an example of the above-mentioned folded type recording head, FIG. 4 is a plan view of the same, and FIG. 2 shows a folded electrode 9 and FIG. Parts that perform the same operations as in the example shown are given the same reference numerals as in FIG. The folded recording head prints one dot at two locations on the heating resistor, and has a wiring density twice that of the recording head shown in FIG. Manufacturing becomes difficult. In particular, in a bubble jet head, since it is necessary to discharge ink from an end face, this folded type recording head has been conventionally used. However, there is still a problem in increasing the density. In order to solve the above problems, a recording head having a multilayer electrode structure has been proposed.

FIG. 5 is a sectional view of an essential part for explaining an example of a recording head having a multilayer electrode structure proposed by the present applicant (Japanese Patent Laid-Open No. 1-115640). 11 is a first electrode (common electrode), 12 is an insulating layer, 1
3 is a heating resistor layer, 14 is a second electrode (selection electrode), 1
5 is a protective layer, 16 is a bonding pad of a first electrode (common electrode), 17 is a bonding pad of a second electrode (selection electrode), 18 is a heating section, and the lower common electrode 11 is an insulating layer 12.
Heating resistor layer 1 through contact holes provided in
3 through the heating resistor layer 13 between the lower common electrode 11 and the upper selection electrode 14 in accordance with a recording signal, thereby generating heat in the heating portion 18. Thus, heat is applied to the heat-sensitive recording paper, or bubbles are generated in the ink to eject ink droplets. However, in the above-described conventional recording head having a multi-layer electrode structure, there is a problem that the lower first electrode (common electrode) functions as a heat radiator, and the thermal efficiency is reduced.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has been made in order to achieve a high density recording head having a multi-layered electrode structure and to prevent a decrease in thermal efficiency. is there.

[0006]

To achieve the above object, the present invention provides (1)
An insulated substrate, a first electrode layer formed on the substrate, an insulator layer formed on the first electrode layer, and a heating resistor formed on the insulator layer And a second electrode pattern layer formed on the heating element resistor pattern layer, wherein the first electrode passes through a contact hole provided in the insulator layer. In the recording head connected to the layer, at least below the pattern portion of the heating resistor pattern layer, the first
No electrode layer, and (2) a heat-resistant resin layer or a heat-resistant resin layer and an inorganic insulator film formed thereon at least in a concave portion of the first electrode layer where the first electrode layer is not provided. (2) providing a two-layer structure or an inorganic insulator film to smooth the recess, or (3) providing an insulated substrate, a first electrode layer formed on the substrate,
An insulator layer formed on the electrode layer, a heating resistor pattern layer formed on the insulator layer, and a second electrode pattern layer formed on the heating resistor pattern layer Wherein the first electrode is connected to the heating resistor pattern layer through a contact hole provided in the insulator layer, wherein at least a first portion below a pattern portion of the heating resistor pattern layer is provided. It is characterized in that the electrode layer is anodized. Hereinafter, a description will be given based on an example of the present invention.

FIG. 1 is a diagram for explaining the manufacture of a recording head according to the present invention. Hereinafter, an embodiment of the present invention will be described with reference to FIG. step1 (Fig. 1
(A)) First, a substrate (a silicon wafer on which an insulating film is formed in the case of a bubble jet, a glazed alumina substrate in the case of a thermal head) 10 is provided on a lower electrode (common electrode) 11.
To form Although the material of the lower electrode 11 is not limited in the first and second aspects, in the case of the third aspect, it is a material that can be anodized (for example, Al, Ta, or the like). step2 (FIG. 1B) Next, a resist pattern 20 is formed by photolithography. step3 (Fig. 1 (c),
(C) ') In the case of claim 1, the material of the lower electrode 11 is removed by etching, and the resist 20 is removed. In the case of claim 2, a two-layer structure of a heat-resistant resin layer, a heat-resistant layer and an inorganic insulator film formed thereon, or an inorganic insulator film is formed in the recess etched in claim 1. These may be formed not only on the concave portions but also on the entire lower electrode surface. However, when formed over the entire surface, the contact portion with the upper electrode and the bonding portion must be removed. In the case of claim 3, the surface of the lower electrode 11 in the resist pattern portion is anodized 21 to remove the resist. FIG.
(C) shows the case of claim 3, and (c) 'is a plan view of (c). step 4 (FIG. 1D) An insulating film 12 is formed. The pattern may be formed by mask sputtering or the like, or may be patterned after forming the entire surface. step 5 (FIG. 1E) Resistor film 13 and upper electrode 14
To form Step 6 (FIG. 1F) The resistive film 13 and the upper electrode 14 are patterned. FIG. (F) ′ is a plan view of FIG. Step 7 (FIG. 1G) A protective film 15 is formed, thereby completing the recording head according to the present invention.

[0008]

As is apparent from the above description, according to the present invention, it is possible to achieve a high-density and to provide a head with high thermal efficiency by a multilayer electrode structure.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a manufacturing process of a recording head according to the present invention and an embodiment of the recording head according to the present invention.

FIG. 2 is a sectional view of an essential part for explaining an example of a conventional recording head.

FIG. 3 is a sectional view of an essential part for explaining another example of a conventional recording head.

FIG. 4 is a plan view of the recording head shown in FIG. 3;

FIG. 5 is a cross-sectional view of a main part for explaining an example of a conventional recording head having a multilayer electrode structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Substrate 11 1st electrode (common electrode) 12 Insulating layer 13 Heating resistor pattern layer 14 2nd electrode (selection electrode) 15 Protective layer 18 Heating part 20 Photoresist 21,22 Anodizing part

Continued on the front page (72) Inventor Yoshio Watanabe 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Eiko Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh (56) References JP-A-62-116166 (JP, A) JP-A-64-61264 (JP, A) JP-A-62-208960 (JP, A) JP-A-63-151468 (JP, A) (58) Fields surveyed (Int.Cl. ⁶ , DB name) B41J 2/335 B41J 2/05

Claims (3)

(57) [Claims] 1. An insulated substrate, a first electrode layer formed on the substrate, an insulator layer formed on the first electrode layer, and a first electrode layer formed on the first electrode layer. A heating resistor pattern layer formed thereon; and a second electrode pattern layer formed on the heating resistor pattern layer, wherein the first electrode passes through a contact hole provided in the insulator layer. In the recording head connected to the heating resistor pattern layer,
A recording head, wherein the first electrode layer is not provided at least below a pattern portion of the heating resistor pattern layer. 2. A two-layer structure of a heat-resistant resin layer or a heat-resistant resin layer and an inorganic insulator film formed thereon at least in a concave portion of the first electrode layer where the first electrode layer is not provided, or an inorganic insulator. 2. The recording head according to claim 1, wherein a film is provided to smooth the recess. 3. An insulated substrate, a first electrode layer formed on the substrate, an insulator layer formed on the first electrode layer, and a first electrode layer formed on the first electrode layer. A heating resistor pattern layer formed thereon; and a second electrode pattern layer formed on the heating resistor pattern layer, wherein the first electrode passes through a contact hole provided in the insulator layer. In the recording head connected to the heating resistor pattern layer,
A recording head, wherein at least a first electrode layer below a pattern portion of the heating resistor pattern layer is anodized.